System of electrical distribution.



H. L. TANNER.

SYSTEM OF ELECTRICAL DISTRIBUTION.

APPLICATION FILED AUG.28, 1914.

1,276,827. Patented Aug. 27, 1918.

3 SHEETSSHET l.

IN VEN TOR.

WITNESSES H. L. TANNER,

SYSTEM OF ELECTRICAL DISTRIBUTION.

APPLICATION FILED AUG.28, 1914.

1,276,827. Patented .27, 1918,

3 SH SHEET 2.

' IN VEN TOR WI TN ESSES fiwvr L 7Z/v/vm UNITED STATES PATENT carton.

' HARRY L. TANNEB, or BROOKLYN, NEW YORK, nssronoza TO srnaar eraoscorncoin- PANY, or BROOKLYN, NEW YORK, a CORPORATION or NEW YORK.

. SYSTEM OF ELECTRICAL DISTRIBUTION.

p a t s s 'ste t Patented Aug. 27, 1918.

- Application filed au st as 1914'; Serial No: 859,087.

tion.

This invention frelates to systems of electrical distribution. in. whichthe primary source of power is: either-.var1able or inter-- mittent, orboth variablefand intermittent. My invention'is adapted-for'useas asystem of electric lightin for railwa and automobiles, and or .many oter uses which will be apparent to those skilled in the art. Theprincipal object of my inventionis to devise an apparatus by which thevoltage on the load is kept constant, irrespective of enerator isrunning whether the primary fast or slow, or has entirely stopped. Otherobjects of the invention will ecome apparentas the description proceeds.

There are two general systems of train lighting in use today one ofwhich emplo s a single generator run at a comparatlve y constant speedby a steam turbine or engine on or near the locomotive, which furnishescurrent to all of the cars. Each car is equipped with a storage battery.The other uses a dynamo on each car belted to the axle, also withstorage batteries. My system is adapted for either system, but it isespecially useful in the axle system, since greater variation in thegenerator speed is found in it.

Several specific embodiments of my invention are shown on the drawings,in which Figure l isa wiring diagram of an axle system of car lightingconstructed according to my invention. Fig. 2 is a similar diagram of myinvention as applied to the other system of car lightin referred toabove, showing also slight mo ifications. Fig. 3 is diagrammatic view ofa single dynamo electric machine adapted to perform the functions ofboth machines shown in Fig. 1. Fig. 3 also shows a self regulatingsystem without the use of storage batteries. Fig. 4 shows a modificationof the machine shown in Fig.

3. Fig. 5 is a diagrammatic view showing the underlying princi les ofthis type of machine. Fig. 6 isa ront elevation of my special type ofcontact making voltage regulator. Figs. 7 and 8 each show curves usedtrains j explaining the theory of operation of my invention.

Referring specifically to Fig. 1, 1 represents any type of generator,adapted to. be

driven from a car axle. It is shown as provided with shunt type of fieldwinding 2. Coupled with said generator is a dynamoelectric machine 3,provided with field wind- ;ings 4; and 5. Reversing switches 6 and 7 areshown in the armature circuits, which maybe operated by any means,automatic or otherwise, so as to reverse the armature circuits, whenthecar is run in the opposite direction, so that the machine may build upand so that the circuit. through the secondarv cells 8 will not bereversed. The load or translating devices 9 .are connected permanentlyin the battery circuit, and the charging dynamos l and 3 areautomatically connected with and disconnected from said circuit.

In my system, the connection is made to depend upon the voltagefurnished by the charging dynamos orin other words, upon the voltage ofthe supply source, so that when its potential falls below apredetermined amount, it is thrown out and vice versa. This result isaccomplished in the embodiment shown by means of a solenoid '10 in thesupply circuit which will draw the armature 11 over against contact 12ifthe solenoid is energized sufficiently to overcome I the effect ofspring 13, which normally holds said armature against contact 1 1.Since, however, the charging. voltage of batteries is always somewhathigher than their discharging voltage, I employ special means .tomaintain the voltage on the load constant, said means being in the formof a resistance 15 in the battery circuit which is operative to reducethe voltage only when the supply circuit isconnected. I accomplish thisby shunting said resistance through a wire connecting contact 14directly with the load circuit when the supplp source is disconnected.

' he generating set 1 and 3 is of special construction, designed to keepthe voltage.

on the load constant through Wide fluctuations in speed. Although it maybe used in conjunction with batteries as shown in Figs. 1 and 2, itsaction is entirely independent of the batteries as shown in Fig. 3.

The dynamo-electric machine 3 is placed .in

- comprises series between generator 1 and the load. ,As stated abovethe machine 3 is provided w th field windings 4 and 5. No specialwinding is required, however, sincg machine 3 may be a standard shuntwound generator n every respect exceptthat a resistance 16 1s tapped inbetween the field coils thereof. Of course two separate windlngs may beprovided, if desired, and also res stance 16 may be incorporated as apart oi the field winding or made as a separate resistance as desired.so that the machine will l'lOt'blllld up normally. A vibratory contactmaking voltage regulator is connected to each end of the resistance 16.Essentially, this instrument a solenoid 17 connected in parallel withthe load. The armature 18 of the solenoid vibrates between contactpoints19 and 20, which are connected between the resistance and thecoils 4 and 5 respectively. Condensers 21 may be provided to reducesparking. A spring 22 opposes thepull of solenoid 17 and the two are soadjusted that the spring will hold the armature switch 18 againstcontact 20 until the voltage on the load exceeds a predetermined amountwhen the solenoid 17 will drawswitch 18 against contact 19. Inoperation, the switch vibrates rapidly between the contacts.

Taking up now the action of the voltage regulator on the field C01lS 4and 5 let us suppose that X is positive and that the generator l isfurnishing a voltage considerably lower than that which is beingmaintained across load 9 and switch 18 is in contact with 20. Machine .3will then act as a booster or generator, pumping current in the samedirection as generator 1. If-the upper brush 50 is at the higherpotential, and switch 7 is thrown to the right, current will flow fromthis brush to coil 5, where it will divide, the main .part' going to theload, while the shunted portion {will fl ow up through coil 5 and W111divide at point 25, a portion going through switch 18, directly to apoint of relatively low potential preferably to main return circuit y,through a resistance 24, while the remaining portion of the current willflow through resistance 16 and coil 4 and to the other brush 51. Theapparatus is so designed that when these conditions are present, thebooster will, under normal conditions, build the voltage up'above thedesired voltage, causing solenoid 17 to draw armature 18 into contactwith point 19. This throws resistance 16 in series with coil 5 whichwould.

tend toreduce the current in said coil. At the same time a circuit fromthe positive to the negative side. of the line is formed down throughcoil 4 to point 23, to contact 19 through armature 18 and resistance 24,thus introducing an electromotive force in coil 4, in such direction asto oppose the current Resistance 16 is made high enough.

then flowing. This new E. M. F. is at first opposed by the inductance ofcoil 4 and hence the effect at first is merely to reduce the currentflowing through said coil. Thus the strength of both fields 4 and 5 willbe lessened which will immediately reduce the boosting efi'ect-of themachine. If at this point in the cycle of operation the voltage issufficiently reduced, the switch 18 will again be returned to point 20and this cycle repeated. But if at said point the voltage is notsufiiciently reduced the switch will remain up a little longer theinduction of coil 4 will be overcome and the current through coil 4 willreverse and start to build up in the reverse direction. At this point itwill be noted that coils 5 and 4 are opposing each other. Coil 4 willspeedily build up stronger than coil 5 and as soon as this occurs thewhole machine will start to act as a bucker and produce an electromotiveforce opposed to that of the main line. This will reduce the E. M. F.across coil 5 and will if continued produce a counter E. M. F. whichwill reverse it, causing it to assist coil 4 in producing a magneticfield. The above cycle is what would take place if switch 18 remains incontact with contact 19 for a sufiicient length of time, but of courseif at any time during that period the voltage on the load falls, 2.suflicient amount, this contact will be broken and a contact throughpoint 20 completed which will start a cycle similar to the one justdescribed, but acting to cause the opposite eflect, the first being asbefore. to weaken the field of the bucker by a counter electromotiveforce impressed across coil 5 and a resistance thrown in circuit withcoil 4. It will at once be recognized by those skilled in the art thatthe periods of time occupied in completing a cycle or a portion thereofare very short, so that in operation the switch 18 vibrates rapidly. Ialso wish it to be understood that the above description of theelectrical reactions of the apparatus embodies only the most pronouncedand essential features, the minor eflects being omitted for the sake ofclearness. What I have provided is, a single regulating means which willnot only vary the field strength of the machine 8, but will reverse thefield, thus doubling the range of regulation.

Meansmay also be provided to cause the voltage on the load to rise whenthe load is heavy, to compensate for the R. I. drop. A second winding 26is placed upon the solenoid 17, which winding is connected in serieswith the load. A variable resistance 27 may be connected in parallelwith said winding so that the amount of current it receives may be'regulated. Winding 26 opposes winding 17 so that the regulator willboost to a higher voltage when heavy currents are being taken. Coil 26is shown as tapped into that portion of the circuit short andillustrates the adaptability of my invention for difi'erent uses. Theinvention is here shown as a booster, and may conslst merely of mypreferred form of machme 3 corresponding to .machine'3, driven as agenerator by any suitable source of power,

thenormal voltage of the machine would be E for the following reason:Suppose that such as motor 127. Machine 3 is connected in series withthe main supply furnished by generator 1. As applied to a train,llghting system, 1' would be driven by means of a small steam turbineor the like near the on s gine, while a set 127-3 is placed on each car.The regulating features of this system are the same in principle as thatshown in Fig. 1, and the parts are correspondingly numbered.Certainmodifications and simplifi cations are shown however. Reversing.

' switches 6 and'7 become unnecessary. The] resistances corresponding tores stance 16 are made of somewhat difi'erent form to reduce sparking. Aresistance 29 is provided a tap being taken into the said resistancedirect to the wire containing resistance 24. and leading to the returnwire 3 By this means the circuit is never broken, so that sparking atpoints 19 and 20 is reduced. A second resistance 28, in multiple with 29may also be used.

The use of my invention illustrated in this figure, i. e., as a voltageregulator for aportion of a variable main circuit, illustrates theadaptability of my invention for difl'erent uses. This figure alsoillustrates the pre-' ferred form of my invention. While the set 127-3is referred to as a motor-generator set, in operation machine 127 actsas a generator when the voltage of the regulated line is materiallyabove the voltage of the main line, or, in other words, when machine 3is acting as a bucker.

I am aware that voltage regulators have been proposed, comprising a maingenerator and an auxiliary generator, both of which are provided with aplurality of separate, differential field coils. In all of thesemachines however, the wiring is very c0mplicated and the set or machineis incapable of operation as a motor-generator, boosterbucker set. In myapparatus neither ma-. chine need be provided with any special windings,and furthermore machine 3 or 3" is entirely independent of machine 1 or127. Thus in Fig. 2, machine 127 could be replaced by any other ty e ofengine or motor without materially a ecting the operation of theregulator. In order that the theory upon which my regulator works may beclearly understood and its operation distinguished from existing typesof regulators, reference is had to Figs. 7 and' 8.

In Fig. 7 o,b,w, is the saturation curve of the generator 3 in whichterminal voltages are plotted as ordinates, and ampere turns fieldexcitationare plotted as abscissae. The stralght line oba is a curvebetween terminal voltage as ordinates and the ampere turns the terminalvoltage momentarily dropped to E The voltage applied to the field wouldalso drop to E and tho field excitat1on would drop to I T,, but as onlyLT,

gampere turns are required to produce the ter m nal voltage E it will beseen that the voltage will rise until E is reached where the ampereturns of the field and the field excitation required to produce thisvoltage are the same. Similarly if the voltage [momentarily rises to' Eit is seen that the field excitation will become I T, while the fieldexcitation I T, is required to produce this terminal voltage so thevoltage will not be maintained but will drop back to E I where the fieldexcitation is just sufficient to maintain the voltage.

Flg. 8 is similar to Fig.7, excepting that it is plotted for bothpositive and negative values of terminal voltage for field excitationand that additional lines are added. The curve ao'a, which correspondsto the curve 0a of Fig. 7, becomes 00 when armature 18 makes contactwith 20, and it becomes 66' when armature 18 makes contact with 19, thecurves 0c and 66' being the algebraic sum of ace and additionalexcitation due to the current which passes through contact 18 andresistance 24, this excitation being considered positive when armature18 is in contact with 20 when the current passes v through coil 5,andnegative when in contact with 19, at which-time the current passesthrough coil 4.

Suppose it is desired to maintain the voltage at E As the armature 18will always be in contact with 19 or 20, the total field excitation mustbe either that shown by the intersection of the curve 00 and thehorizontal line E or that shown by the intersection of the curve cc andthe line through E From the description of Fig. 7 it will be seen thatif the machine is operating on curve era the voltage will be reduceduntil point f is reached; and if operating on curve co the voltage willincrease. until point 03 is reached.

Suppose the armature. to be in contact with 20, then the machine wouldbe working on curve 00 and the voltage will begin to rise; as soon as itrises a slight amount, however, solenoid 17 will become stronger,drawing armature 18 away from contact 20 and making contact with 19,when the machine will be operating on curve ee'. Then the voltage willbegin to fall, until the solenoid 17 becomes weakened sufficiently toallow spring 22 to pull armature 18 back making contact with 20, afterwhich the above cycle will be repeated.

For the machine to operate as described, resistances 24 and 16 must begiven such values that curve ee will lie to the left of a tangent tocurve obm, and curve 00' will lie to the right of a tangent to obw.Suppose this were not true but that the resistance were given suchvalues as to make curve 66' fall at ff and 00 fall at kh. If an attem tbe then made to maintain the voltage 'at 1 when the armature makescontact with 19, the field excitation will be greater than that requiredto maintain this voltage, and the voltage will rise until point 9 isreached, where the voltage will stick.

IVhile the regulator normally operates in the cycle described, this maybe modified.

slightly by designing the solenoid 17 and the armature 18 so that thearmature 18 may be made to stand in a position where it will touchneither 19 nor 20. In this case resistance 16 must be of such value asto change curve amt to some such curve as a0a," where every part ofsection 0a of the curve lies to the left of curve obw and every part ofthe curve 000' lies to the right of curve 07m,- in other words, thevalue of resistance 16 must be such as to kill the voltage of themachine when armature .18 makes contact with neither 19 nor 20.

In Fig. 3 is shown a dynamo-electro machine 100 which performs thefunction of both machines 1 and 3 shown in Fig. 1. It embodies the samefundamental principles of operation, but only one armature Wind'- ingand one commutator 33 are used. In the machine illustrated, the dynamois a standard bi-polar shunt wound generator equipped with an auxiliarypair of poles 30, and an auxiliary brush 31. The main brushes 32correspond in number to the armature windings and are positioned in thecommutating zones on the commutator, which are found to occur. when thearmature coils are ent potential on the commutator from the mainbrushes, and in the type of machine illustrated is preferably placedmidway between them as poles 30 and 36 are shown as being of the samewidth. The windings 4: and 5' on the auxiliary poles 30 correspond tofield windings 4: and 5 respectively. They are connected at one end tothe auxiliary brush 31, and at other end to the external'circuit w. Aresistance 16 and the voltage regulator are placed between the two asbefore. The auxiliary fields are thus made to oppose or aid the mainfields 36.

The general theory of the operation of assing between two poles.- Brush31 is positioned at a point of difi'erthis machine and its analogy tothe set shown in Fig. 1 is shown in Fig; 5. At any given instant thearmature may be considered to be divided by the brushes into twosections, one of which,'34: composes the two diametrically oppositequadrants under pole pieces 36, while the other 35 composes the twoquadrants under pole pieces 30. Also since the brush 31 performs adouble function, it is shown as two brushes 31 and 31. It will readilybe seen that that section of the armature between brushes 31 and 32" (i.c. section 34) together with poles 36 corresponds to and performs theunction of generator 1 in Fig. 1 while section 35, between brushes 31and 32 corresponds to dynamo-electric machine 3 of Fig. 1 The windingson poles 36 are shunted acrfi'ss the main supply wires, as is the casewith field coil 2, while coils 4 and 5 are placed in series with brush31 and the external circuit as explained above. If brush 32 were thenegative main linebrush and no current were flowing through coils 4and-5 brush 31" would furnish the entire potential of the line, brushes31 and 32 being practically at the same potential. Now suppose the speedof the armature to be reduced so that the potential at brush 31 falls.The first slight resultant drop in the external circuit will immediatelybe detected by my voltage regulator, which will cause the right handpole 30 to become a south pole and the opposite one a north pole by themeans heretofore described and 106 hence cause a rise in the potentialfrom brush 31 to 32 which would exactly compensate for the loss ofpotential at brush 31, thus maintaining the external voltage constant.Similarly, if the speed of the 105 armature was increased, the potentialat 31 would rise and by means of the voltage regulator, the left handpole 30 would become a south .pole and the right hand a north pole. Thiswould cause a fall in po- 110 tential from brush 31 to 32' compensatingfor the increased voltage at 31.

The voltage regulator is the same type as that used in Fig. 1.' Nostorage batteries are shown, however, to emphasize the fact 115 that theoperation of my regulator is in-no way de endent upon batteries and thatit is adapte for use in any circuit.

A modification 101 of the dynamo-electric machine is shown in Fig. 4 Themachines in Figs. 3 and 4 are shown as identical except that brush 31 isomitted on machine 101 and the winding 4 and 5 are connected through amanually or otherwise operated rheostat 40 and reversing switch 41, inmultiple with the external circuit. We have, then, a multip'olargenerator with both primary and auxiliary pole pieces, an armature woundwith reference to said primary poles only and brushes '32 to comespondto the armature winding ositioned in the commutating zone. The r eostat40 and reversing switch 41 may be operated to vary the strength orreverse the polarit of pole pieces 30 so that the same resu t isachieved as by use of the vibratory regulator This form of machine isespecially adapted where the speed of the source of power is constantmost of the-time but is subject to considerable changes at times, whilethe other forms are more adapted where the speed of the source of poweris seldom steady. i

The instrument which I term the master voltage regulator and which isshown diagrammatically in Figs. 1, 2, and 3 preferably assumes the formshown in Fig. 6. It is made in the form of a motor 42. The fieldwindings 17 of this motor correspond to the solenoid 17, while armature18 corresponds to armature 18. Armature 18' is mounted on shaft 43 onwhich is secured the bar 44. A spring 22' tends to draw the arm intocontact with contact point 20 while the armature 18 is so placed thatthe torque exerted on it by solenoid 17 opposes the force of the springand tends to draw the arm in cont-act with point 19'. The actual Icontacts are made through spring arms 44 and 45, which cause a wipingcontact over points 20' and 19' so that the contacts may be kept clean.Contacts 19 and 20 are made in the form of screws 46 adjustable inthreaded blocks 47 fixed on the base 48. Lock nuts 49 are also provided.The tension of spring 22 is rendered adjustable by securing one end to athread 50 which is secured to a'rod 51,v rotatably mounted in thefriction bearing block 52, so that the thread may be wound upon orunwound from said rod.

This type of contact making regulator possesses many advantages over theusual type, which is illustrated in the wiring diagrams, since it isperfectly balanced about every axis and hence will work in any positionand when subject to jolts and jars which would seriously interfere withthe existing type. In operation the arm 44 vibrates rapidly betweenpoints 19 and 20', causing a continual fluctuation in the impressed E.M. F. on the field-coils 4 and 5, but the fluctuation is so rapid thatthe voltage on the load is kept constant.

From the foregoing it is believed that the operation of the severalparts of my system will be clear and also that it will be apparent thatcertain of the features set forth in the appended claims are of-greatindividual importance. To restate briefly the operation of the system asa whole, I will suppose that the car carrying the apparatus shown inFig. 1 is at rest and the lights are burning. The battery will thenfurnish the entire supply andthe main part of the current ating set andthus both charging the bat- I teries and lighting the lamps. The lamp.

current now however, will go through resistance 15 which allows a risein voltage on the battery so that it may be charged. As the car speedsup, the supply voltage is prevented from rising by the booster-buckerand its regulating means, the boosting effect of which becomes less andless until it finally begins to buck or furnish a counter E. M. F. whicheffect becomes more powerful as the car speeds up, Although it thus actsto keep the voltage down, it does not-cause an ap-' preciable loss ofpower, .as when acting in this capacity, it really acts as a motorandhelps to drive the generator 1.

In accordance with the provisions of the patent statutes, I have hereindescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodimentsthereof, but I desire to have it understood that the apparatus shown isonly illustra-. tive and that the invention can be carried out by othermeans. Also, while it is designed to use the various features andelements in the combination and relations described some of these may bealtered and others omitted without interfering with the more generalresults outlined, and the invention extends to such use.

Having now described my invention, what I claim and desire to secure byLetters Patent is: m

1. A voltage regulator adapted to be connected with a line to beregulated comprising a dynamo-electric machine, a plurality of fieldwindings thereon in series with one another, means for causing a drop inpotential between said windings whenever current flows from one toanother of said windings, and means for varying the potential dropbetween said windings responsive to variations in the voltage on theregulated line when said regulator is operatively connected to saidline.

2. A voltage regulator adapted to be connected with a line to beregulated comprising a dynamo-electric machine, a plurality of fieldwindings thereon in series with one another, means interposed. betweensaid windings for causing a potential drop therebetween whenever't-hereis a flow of current from one to another of said windings, and meansresponsive to variations inthe voltage cuit around said first mentionedmeans.

3. A voltage regulator adapted to be connected with a line'to beregulatedcompr singa dynamo-electric mach1ne, a plurality of fieldwindings thereon in series with one another and means for varying thepotential dro between said windings responsive to varlations in thevoltage on the regulated line and also to variations in the amount 'ofcurrent taken by the'said l ne when said 16 v nected with a line toregulator therefor comprising a -ever current flows from one regulatoris connected to said line, the terminals of the series connectionbetween sa1d windings being at a difier'ent potentlal whenever currentflows from one to another 0 said windings. I

4. A voltage regulator adapted to be conbe regulated comprising adynamo-electric machine, a plurality of field windings therefor inseries with one another, windings in series flo'w' of current throughtherewith there being a regulator is connected to said for completing acircuit around said resistq ance from a point adjacent the connection ofa winding with said resistance to a point of different potential andmeans for creating a difference of potential between. said points. 6. Incombination, a line circuit, a voltage regulator therefor comprising adynamoelectric machine, a plurality of field windings therefor in serieswith one another, a resistance placed between said windings in seriesriations in the voltage of the regulated line for completing a circuitaround said resistance from a point adjacent the connection of either ofsaid windings with saidresistance to a point of different potential andmeans for creating a difference of potential between said points.

7. A voltage regulator comprising a dynamo-electric machine adapted tobe placed in series with a variable line, a shunt field circuit thereforhaving aresistance high enough to prevent the building up of themachine, means for causing the building up of the machine by completinga circuit including a source of E. M. F. around a portion of the fieldwinding, and means for driving said machine. 7 8. In combination, aline, a voltage regulator comprising a dynamo-electric machine in serieswith said line, a shunt field circuit a reslstance placed betweensaidsaid resistance whena circuit around said resist-' therewith, meansresponsive to vatherefor having a resistance high enough to prevent thebuilding up of the machine, means connected to said line and responsiveto variations in the voltage beyond the machine for causing the buildingup of the latter by completing a circuit, including a source-of E.M.'F., around a" portion of-the field winding, and means for drivingsaid machine.

9. In combination, a line, a voltage regulator comprising adynamo-electric machine in series with said line, a shunt field circuittherefor having aresistancehigh enough to prevent the building up of themachine,

means connected to said line and responsive to variations in the voltagebeyond the machine for causing the building up of the machine in eitherdirection by completing acircuit around one portion or another of thefield circuit.

tric machine in series with said variable line, a shunt field circuittherefor having a resistance high enough to prevent the build- 10. Incombination, a variable line, a voltage regultor comprising adynamo-elecing up of the machine, means ,connected to v said line'and responsive toa predetermined change inthe voltage beyond the machine for completing acircuit from a point of the fieldv circuit nearer the regulated part ofsaid line to a point of difierent potential, means for driving saidmachine, and means for creating a difference of potential between saidpoints.

11; In combination, a variable line, a voltage regulator comprising adynamo-electric machine inseries with said variable line, a shunt fieldcircuit therefor having a resistance high enough to prevent the buildingup of the machine, means connected to said line and responsive to apredetermined change in the voltage beyond the machine for completing acircuit from a point of the field circuit farther from the regulatedpart of said line to a point of different potential, means for drivingsaid machine and means for creating a difference of potential betweensaid points. I

12. In combination, a supply line, a voltage regulator comprising adynamo-electric machine in series with said line, a shunt field windingthereon, a resistance tapped in between the coils of said winding, meansconnected to said line and responsive to a predetermined change in thevoltage of the line for completing a circuit from a point adjacent theconnection of said resistance to the coil nearer the regulated part ofsaid line, to a point of different potential, means for driving saidmachine and means for creatinga difference of potential between saidpoints.

13. In combination, a supply line, a voltage regulator comprising adynamo-electric machine in series with said line, a shunt sistance tothe coil farther from the regulated part of said line,.to a point ofdifferent potential, means for drivlng said machine and mean forcreating a difference of potential between said points.

" 14. In combination, a supply line, a voltage regulator comprising adynamo-electric machine in series with said line, a shunt field windingthereon, a resistance tapped in between the coils of the said winding,means connected to said line and responsive to a variation in thevoltage of the line for completing a circuit from a point adjacent theconnection of said resistance to the coil nearer the regulated part ofsaid line, to a point of different potential, upon a predeterminedchange in said voltage and for completing a similar circuit from a pointadjacent the connection of said resistance to a coil farther from theregulated part of said line, upon an opposite change in said voltage,means for driving said machine and means for creating a difference ofpotential between said points.

15. In combination, a supply line, a voltage regulating dynamocomprising field coils and an armature, said armature being in serieswith one side of said line, one of said field coils being connected atone end to one side of said line, another of said field coils beingconnected at oneend, to the same side of said line and means governed bythe voltage of said line for alternately connecting the other ends ofsaid above mentioned'coils to the other side of said line.

16. In combination, a supply system, a load supplied thereby, meansforregulating the voltage of said supply system comprising adynamo-electric machine, a, plurality of field coils connected in seriesthereon, and means responsive to variations in the voltage on the loadto cause a variation in the electro-motive force across one ,of saidcoils whereby the resultant field current is in creased, reduced orreversed, dependent upon the direction magnitude and duration of theinitial voltage variation and upon whether that portion of the machineinfluenced by said field coils was acting as a bucker or as a booster atthe time of the voltage variation.

17. The method of regulating the field of a voltage regulatingdynamo-electric machine which consists in impressing a counterelectro-motive force across a portion of the field winding andintroducing a resistance in series with another portion of said windingto cause the current through the first of sa1d then reversed.

18. A method of maintaining a constant voltage on a variable line by thefield regulation of a dynamo-electric machine, characterized by thefollowing cycle as the supply voltage and power gradually increase fromzero, first the building up of the field until the desired voltage isreached, second the simultaneous introduction of a counterelectro-motive force across a portion of the field winding and aresistance in circuit with another portion of the field winding as saidvoltage is exceeded,=third.a reversal of the current in said firstmentioned portion of the I mentioned portion to be first reduced and Ifield winding, fourth the increase in the stren h of said portion beyondthe strength other portion and fifth the reversal of current in saidother portion.

19. Means for regulating the voltage of a supply'system, comprising adynamo-electric machine, a plurality 'of field coils connected in seriesthereon, and means responsive to variations in the voltage on the loadto cause a counter electro-motive force across one of said coils andasimultaneous introduction of resistance into another of said coils.

20. In combination, a supply line, a voltage regulating dynamocomprising a field Wm ing in series with one side of said line, aconnecti 11 between an intermediate point of said fie d winding and theopposite side of said line and means responsive to changes in voltage onsaid line for making and breaking said last named connection.

21. In combination, a line circuit, a voltage regulating dynamoconnected therewith having a field winding of a plurality of parts, aresistance interposed between two of said parts, a source of E. M. F.and means for connecting said source of E. M. F. and said resistance inseries with one or another of the parts of said field according as thevoltage of the line circuit rises or falls.

22. In combination, a line circuit, a voltage regulating dynamoconnected therewith having-a field winding of a plurality of sections, aresistance interposed between two of said sections, a source of E. M. F.and means responsive to variations in voltage on the regulated line forconnecting said resistance to said source of E. M. F.

23. In combination, a supply line, a dynamo comprising field coils andan armature, said armature being connected in sesaid last mentionedfield coils to the other side of said line.

24. In combination, a-supply line, a volta. plurality is winding, anconnecting s line.

of taps from said shunt field d voltage regulated means for aid taps tothe other side of the In testimony whereofI have signed my name to thiss ecification in the gresence of two subscrib ng witnesses,'this 2 thday 10 of August, 1914.

, o HARRY L. TANNEB.

Witnessesf 1 i F. R. AILEN, CHARLES H. (3011mm.

